Among various products for industry and for living, there are some products comprising two or more parts, at least, one of which is applied with decorative or anti-corrosive paint by baking, and which parts are assembled together by bonding with adhesive. FIG. 8, for instance, schematically shows the assembling process of the rotor for a stepping motor. The rotor 10 comprises a ring 12 made of magnetic material such as neodymium-iron-boron (Nd-Fe-B), and a boss 14 made of nonmagnetic metal (SUS304, aluminum, etc.) which is inserted into the ring 12. In this case, the surface of the ring 12 as is magnetic material is apt to rust and is poor-looking, so that it is treated by painting prior to being assembled with the boss 14. That is, as shown in FIG. 8 (1), the surface of the ring 12 is applied with anti-corrosive paint 16 by electrodepositioning paint or spray painting, treated by baking in the heating furnace 18 (electric furnace, gas furnace, etc.) as shown in FIG. 8 (2), and thereafter appropriate adhesive 20 is applied to the inner periphery of the ring 12, as shown in FIG. 8 (3). Then, the boss 14 is inserted into this ring 12 so that the bonded assembly of both members 12, 14 is obtained.
Further, FIG. 9 (1) is a perspective view showing arc pieces of segment magnets 24 bonded at predetermined intervals peripherally to the inner surface of cylindrical yoke 22 in a motor housing, for instance. In this case, also, the surface of each piece of the segment magnets 24 is applied with the anti-corrosive paint 16 by the electrodepositioning painting, etc., treated by baking in the heating furnace, and then bonded to the inner surface of the yoke 22 through the adhesive applied on the baked paint.
In the above-mentioned product for industry or for living that comprises tow or more parts, at least, one of the parts is applied with the paint and thereafter those parts are bonded together to be assembled, so that a separate process is required for applying the adhesive after the completion of the painting. Consequently, it is unavoidable for the manufacturing cost to be increased owing to the increase of numbers of processes and to the use of the adhesive. Furthermore, the adhesive contains a fear that is protrudes from the product as the object of bonding and impairs the dimensional tolerance or results in poor-looking. Moreover, the adhesive contains a problem that the volatile solvent included in itself is vaporized to render the working environment polluted. Furthermore, such fault is pointed out that when the single part to be painted is treated by electrodepositioning painting or spray painting, and thereafter treated by baking, the part easily deforms or produces a strain so that the desired accuracy of the assembled product can not be secured.